pyLoad WindowsPhoneNotify addon: non-admin SETTINGS user triggers SSRF via unguarded http.client notification host

Why it is Yellow

• CVSS 6.4 medium
• Public exploit or proof of concept referenced
• On your watchlist: PyPI

Affected packages

References

• https://github.com/advisories/GHSA-p3pr-8f3m-4qp8
• https://github.com/pyload/pyload/security/advisories/GHSA-p3pr-8f3m-4qp8
• https://github.com/advisories/GHSA-p3pr-8f3m-4qp8

Original description

## Summary pyLoad ships the WindowsPhoneNotify addon, whose `send()` method opens an HTTP connection to a host taken directly from the plugin's `pushurl` configuration value. A user holding the standard non-admin `SETTINGS` permission can set `pushurl` and `pushid` and enable the addon through the web API, since these plugin options are not in the admin-only option set. Once enabled, the addon activates dynamically without a restart, and any completed download (download events fire globally, not per user) causes the addon to send an HTTP POST to the configured host and path. The request is made with Python's `http.client.HTTPConnection`, so it never passes through pyLoad's pycurl-based outbound connection guard. The attacker can therefore direct blind POST requests at internal hosts such as loopback services, RFC 1918 addresses, or the cloud metadata endpoint `169.254.169.254`. ## Root Cause pyLoad enforces its outbound SSRF protection only inside the pycurl request path, where a `PREREQFUNCTION` callback calls `is_global_address()` on the resolved peer IP before each connection. The WindowsPhoneNotify addon uses a completely separate HTTP client (`http.client.HTTPConnection`) that is never subjected to that callback and performs no address validation of its own. In addition, the API config-write authorization only guards a narrow hard-coded set of plugin options, which does not include the WindowsPhoneNotify host and path fields, so a non-admin user can point the notifier at any destination. ```text Affected symbols: - WindowsPhoneNotify.send (src/pyload/plugins/addons/WindowsPhoneNotify.py): opens http.client.HTTPConnection(url) on the attacker-controlled pushurl with no destination check. - Api.set_config_value (src/pyload/core/api/__init__.py): ADMIN_ONLY_PLUGIN_OPTIONS contains only AntiVirus entries, so a non-admin SETTINGS user can write the WindowsPhoneNotify pushurl, pushid, and enabled values. ``` ## Impact An authenticated user with the non-admin `SETTINGS` permission can cause the pyLoad server to issue blind HTTP POST requests to arbitrary internal hosts, ports, and paths that the user cannot reach directly. The attacker controls the destination host and port (`pushurl`), the request path (`pushid`), and part of the XML request body (through file and package names surfaced in the notification text). Because the request is blind, response bodies are not returned; the demonstrated capability is internal service discovery, port and host probing through timing or error differences, cloud metadata endpoint reachability where the network routes it, and triggering state changes on internal HTTP endpoints that act on POST requests. Confidentiality and integrity impact are limited but real; no direct availability impact was demonstrated. ## Proof of Concept ```text Preconditions: an authenticated pyLoad account with the SETTINGS permission (128), a network path from the pyLoad host to the chosen internal target, and at least one download that completes to fire the notification event. ``` 1. As a user with the `SETTINGS` permission, POST to `/json/save_config` with `category="plugin"` and config values `WindowsPhoneNotify|pushurl=169.254.169.254`, `WindowsPhoneNotify|pushid=/latest/meta-data/`, and `WindowsPhoneNotify|enabled=True`. 2. The write is accepted because `(WindowsPhoneNotify, pushurl)` is not in the admin-only option set, and setting `enabled` to true triggers the addon manager's dynamic activation callback, loading the plugin immediately. 3. Allow (or cause) any download to finish. The global `download_finished` event iterates activated addons and invokes the notifier. ```text POST /json/save_config HTTP/1.1 Host: pyload.target Cookie: <authenticated session with SETTINGS> Content-Type: application/x-www-form-urlencoded category=plugin&config=%7B%22WindowsPhoneNotify%7Cenabled%22%3A%22True%22%2C%22WindowsPhoneNotify%7Cpushurl%22%3A%22169.254.169.254%22%2C%22WindowsPhoneNotify%7Cpushid%22%3A%22%2Flatest%2Fmeta-data%2F%22%7D ``` ```text Observed result: on the next completed download, the pyLoad process opens a TCP connection to 169.254.169.254:80 and sends "POST /latest/meta-data/" with a text/xml notification body. The connection is made by http.client.HTTPConnection with no address validation. ``` ## Attack Chain 1. **Exposure:** The `/json/save_config` web endpoint is network reachable and gated only by `login_required("SETTINGS")`, a standard non-admin permission bit. 2. **Control:** The attacker supplies the notifier `pushurl` (host and port), `pushid` (request path), and `enabled` flag as config values. 3. **Path:** `set_config_value` writes the plugin options; the addon manager's config-change callback fires on `enabled` and activates the addon without a restart; a completed download dispatches the global `download_finished` event to activated addons. 4. **Guard:** The config-write check consults `ADMIN_ONLY_PLUGIN_OPTIONS`, which lists only two AntiVirus options, so the notifier fields pass; the notifier rate and client-connection checks do not block the request; the pycurl `PREREQFUNCTION` SSRF guard and `is_global_address` are never invoked on this path. 5. **Primitive:** `WindowsPhoneNotify.send()` calls `http.client.HTTPConnection(pushurl)` and issues a POST to `pushid`. 6. **Result:** A blind HTTP POST reaches an attacker-chosen internal host and path from the pyLoad server's network position. ## Bypass Evidence pyLoad's outbound SSRF protection lives entirely in the pycurl request path: `is_global_address()` is called only from the pycurl `PREREQFUNCTION` callback, and `is_global_host()` is called only from URL parsing for user-submitted download links. Neither helper appears anywhere in the notifier dispatch path. The WindowsPhoneNotify sink uses `http.client.HTTPConnection`, which has no relationship to pycurl and no destination validation, so the guard is not bypassed by a payload trick but is simply not present on this code path. Attempts t